In the prior art several articles refer to the preparation of benzimidazoline-2-thiol derivatives substituted on the sulfur atom. (J. Chem. Soc., 3311-3315. (1949); J. Pharm. Soc. Japan, 74, 1365.-9. (1954), CA: 49, 15876b; Yakugaku Zasshi, 78, 1378.-82 (1958). CA: 53, 8124h; Nauch Doklady Vysshei Shkoly, Khim.i Khim.Tekhnol., 333-337 (1959), CA: 54, 510b; Japaness Patent Application No. 10978(61), CA: 58, 13964h). Thiazino(3,2-a)benzimidazole is described by Current Sci. (India), 32, 454.-5. (1963), CA 59,15275h and Dopov Akad. Nauk RSR Ser. B. 801. (1975), while Japanese Kokai No. 50/52065 and CA 83 206268r relates to the preparation of succinic acid derivatives substituted by benzimidazol-2-yl-thio substituents in position 2.
Though the above articles refer to the possibility of the synthesis, they do not contain any reference to the medical use of the noval compounds of formula I.